1. Field of the Invention
This invention relates generally to an electronic signal processing apparatus, such as, a personal computer, and more particularly is directed to an improved apparatus of that type which the functional capabilities of the apparatus may be expanded by coupling additional signal processing or handling sections to the basic components or sections of the apparatus required for performing the minimal necessary functions.
2. Description of the Prior Art
It has been known to provide a personal computer which can be purchased as a simple or basic apparatus equipped to perform only the minimal necessary functions so as to reduce the initial purchase price of the apparatus and to simplify its exterior appearance. To such basic apparatus there may be added various additional signal handling or processing sections or units for expanding the functional capabilities of the apparatus in accordance with the individual requirements of the user. Among the existing apparatus that permit the selective attachment of additional sections or units for expanding the functional capabilities of the apparatus there is one type in which the housing of the apparatus, in its basic or simple form, already has a space therein for accommodating the additional units or sections to be subsequently added. Thus, the overall dimensions of the housing are dictated by the space required for the additional units or sections needed for the expanded functional capabilities and, for any user not requiring such expanded functional capabilities, the housing of the apparatus is unnecessarily and undesirably large and clumsy.
In another existing electronic signal processing apparatus intended for use as a personal computer, the basic apparatus is provided with a relatively compact housing of a size determined by the equipment to be housed therein for performing the minimal necessary functions, and additional units required for achieving the expanded functional capabilities are separately housed and merely connected to each other and to the basic apparatus by means of flexible cables. In such apparatus, the additional units or sections housed separately from the basic apparatus tend to undesirably increase the space required for the apparatus having expanded functional capabilities. Further, independent power supplies are needed for the additional units or sections, thereby increasing the size and cost thereof. Moreover, the undesirably long connecting cables extending between the basic apparatus and the additional units or sections are liable to cause various problems, such as, signal deterioration, power supply disturbances and undesired radiation.